A general projector is manufactured based on a premise that an image is projected on a flat wall surface. In such a projector, an image to be projected on a wall surface may be distorted depending on a positional relationship between the projector and the wall surface. For example, when a projecting direction is not straight with respect to a wall surface, an image may be projected with different magnification ratios between a vertical direction and a horizontal direction. In such a case, it is possible to eliminate distortion of an image by using a keystone correction function. PTL 1 discloses an example of keystone correction.
In order to appropriately project an image on a wall surface, it is effective to actually capture an image projected on the wall surface, and to perform correction, based on the captured image. PTLs 2 and 3 disclose devices for capturing a projected image and adjusting the projected image, based on a captured pattern.
Further, in order to project an image to be projected on a curved surface, a technique other than keystone correction is necessary. PTL 4 discloses a technique for correcting distortion of a displayed image even on a surface having unevenness or a projection surface of a curved surface.